Nuclear arms race would weaken US security

President-elect Donald Trump tweeted in late December that the United States “must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes”. Soon after he declared: “Let it be an arms race,” and asserted that the US would win it. Trump appears to be committing a major mistake.
Like any other country, the United States warrants legitimate national security. The US first developed nuclear weapons through the Manhattan Project, aimed at keeping pace with Nazi Germany’s nuclear weapons programme and also to counter imperialist Japan’s aggression. But since then, the US has often abused its nuclear policy. By flexing its nuclear muscles, the US pushed the Soviet Union to expedite its atomic weapons programme in the late 1940s. By threatening China with a nuclear attack during the Korean War (1950-53), it forced Beijing to launch its own programme in the mid-1950s. And by waging an unjustified war in Iraq, the US taught North Korea the importance of possessing nuclear weapons.
Despite several rounds of nuclear disarmament, the US still deploys thousands of such weapons and has many more in its vaults. Russia has built a nuclear arsenal as powerful, and China seems to have developed a cost-effective minimum deterrence designed to drive sense into potential rivals.
When Trump promised to strengthen the US nuclear arsenal so as to bring other countries to their senses, one wonders which countries he had in mind. Does he mean to wage a nuclear race with Russia, since Moscow is the only power whose arsenal rivals or even outstrips that of the US?
Incumbent US President Barack Obama “reset” Washington’s relations with Moscow in 2009 despite the Russia-Georgia conflict in 2008. And after Crimea’s inclusion in Russia in 2014, Trump seems interested in again “resetting” relations. This contradicts Trump’s own promise of “expanding nuclear weapons credibility”, and could lead to another Georgia- or Ukraine-like crisis.
Or does Trump have an eye on China? Over 60 years ago Beijing decided to go nuclear given the US nuclear “blackmail”, and succeeded. Before Beijing tested its new weapons, the US made a dozen nuclear threats against China. But since 1964, when Beijing detonated its first nuclear device, the US has declined to issue any threats, vindicating the power of China’s deterrence.
China has maintained a practical nuclear strategy of minimum deterrence, which has both boosted national security and allowed it to avoid an unnecessary arms race. At a time of resource scarcity, China’s approach was certainly a smart one. But times have changed. The World Bank announced China became the world’s largest economy (in terms of purchasing power parity) two years ago. As long as China doesn’t perceive an increase in external threats, Beijing can maintain its current policy. But if Trump forces other countries into a nuclear arms race, he could wake up to find America’s nuclear credibility in decline.
Rather than winning an atomic arms race, US national security could weaken vis-a-vis even North Korea. Given its rising capability to build long-range ballistic missiles, even Pyongyang could deter the US to an extent, rather than merely the other way around. 
The US is already secure, and doesn’t need further expansion of its nuclear arsenal, which could instead trigger a race that America might not win. Thus, the Trump administration should see the nuclear danger for what it is, and work with other countries for disarmament.

Shen Dingli is a professor and associate dean at Fudan University.